Automatic punching machine



Nov. 3, 1959 T. M. WRIGHT 2,911,045

AUTOMATIC PUNCHING MACHINE 7 Sheets- Sheet 1 Filed March 10, 1955 IN VEN TOR.

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AUTOMATIC PUNCHING MACHINE Filed March 10, 1955 7 Sheets-Sheet 4 Nov. 3, 1959 T. M. WRIGHT AUTOMATIC PUNCHING MACHINE Filed March 10, 1955 Nov. 3, 1959 T. M. WRIGHT AUTOMATIC PUNCHING MACHINE T Sheets-Sheet 6 Filed March .10, 1955 IN VEN TOR. mam/0,1914% BY AZYZ'OBJVEY Nov. 3, 1959 T. M. WRIGHT AUTOMATIC PUNCHING MACHINE 7 Sheets- Sheet 7 INVENTOR.

7Ze0dare Mllz'glzf BY l-ILJ Filed March 10, 1955 United States Patent 2,911,045 AUTOMATIC PUNCHING MACHINE Theodore M. Wright, Camden, N.J., assignor to Radio Corporation of America, a corporation of Delaware Application March 10, 1955, Serial No. 493,406 7 Claims. (Cl. 164-115) This invention relates to a programmed punching machine, and more particularly to an automatic machine for punching a pattern of small holes in sheet materials, such as phenolic boards.

In the development of electronic apparatus for mass production, increasing attention is being given to the use of printed circuits which facilitate the use of automatic methods in the production and assembly of such apparatus. One type of printed circuit which is widely used is made up of a thin, conductive layer, such as copper, rigidly fixed to a phenolic board. The circuit is formed by removing a certain portion or portions of the copper layer from the board leaving conductive strips in accordance with a predetermined pattern. Components are fastened to theboard by assembling them to the face of the board opposite from the conductive layer and passing the terminals of these components through apertures provided in the board for engagement with the conductive strips.

The principal object of this invention is to provide an improved automatic punching machine for programming and punching small apertures in a sheet of material, such, for example, as a copper coated phenolic board.

Another object of this invention is to provide an improved punching machine for punching holes in a phenolic board in accordance with a pattern laid out on a'flexible sheet of material.

.A further object of this invention is to provide an improved automatic punching machine wherein perfect registry is always provided between the master pattern and the board being punched. V

A still further object of this invention is to provide an improved automatic punching machine wherein both a master pattern and the board being punched are advanced in intermittent steps and wherein the pattern and the board are advanced alternately. p

A still further object of this invention is to provide an improved automatic punching machine wherein the mechanism for advancing a board to be punched and the mechanism for advancing a master pattern are directly coupled, and wherein these mechanisms may be selectively disengaged from the machine power source.

.Astill further object of this invention is to provide an improved automatic punching machine wherein a rela- :tively heavy sheet material may be punched.

In accordance with the present invention a machine is provided for the punching of a sheet material. This machine comprises a punch head carrying a single row of floating punches. The sheet is intermittently stepped beneath the punching head in a direction transversely of the row of punches and the punching headcarries the punches toward the sheet after each movement of the sheet. The individual punches do not act to .punch a vhole in the sheet unless an interference member is positioned above the punch. Interference members are provided for each of the punches in the punching head and 'are positioned by means of electromagnetic devices the sheet. The master through suitable linkage. The selection of punches is controlled by a master which comprises a pattern cgrrespending to the hole pattern desired to be punched in is carried past a sensing mechanism which senses the pattern on the master and selects the proper interference members so that the proper holes are punched in the sheet material by the punching head.

The driving means for the master is directly coupled to the sheet carrier so that perfect registry is always maintained between the master and sheet during either manual or automatic operation of the machine. These elements are coupled by a mechanism which provides for the alternating intermittent movement of the master and sheet resulting in considerably speeded up operation of the machine.

The novel features of the invention as well as additional objects and advantages thereof will be understood more fully from the following description when read in connection with the accompanying drawings, in which;

Figure 1 is a perspective view showing the top of a machine in accordance with the present invention;

Figure 2 is a view in front elevation, partially broken away, of the machine of Figure 1;

Figure 3 is a view in side elevation, partially broken away, and partially in section, the section being taken on line 3-3 of Figure 2 looking in the direction of the appended arrows;

Figure 4 is a sectional view of the punching head and associated parts of the machine;

'- Figure 5 is a view in plan of aprinted circuit panel illustrating end notches provided for locating the panel on the machine; t

Figure 6 is a view in side elevation and partially in section of the carrier to .which the circuit board is attached, this view being taken of the detached part to the left of the line 6-6 of Figure 3 as indicated by the appended arrows; 1

Figure 7 is a top view of the carrier illustrating the locking fingers for positioning the printed circuit board;

Figure 8 is a fragmentary section of theme chanism for coupling thecircuit board carrier and the master driving drum, the section being taken along the line 8--8 of Figure 3 looking in the direction of the appended arrows;

Figure 9 isa detail "view, partially broken away, of the contgol mechanism for the coupling mechanism of Figure I Figure 10 is a top view of the drums for carrying the perforated master and illustrating the reader bar and associated mechanism which cooperates with the perforated master; v

Figure 11 is a view in side elevation, partially broken away, illustrating the drums, reader bar and associated mechanism of Figure 10; and

Figure 12 is a detail view, partially in section, of a switch assembly, the section beingtaken along the line 12-12 of Figure 11 looking in the direction of the. appended arrows. y Y

Referring now in more detail to the accompanying drawings, the present invention is embodied in a machine for punching holes in a printed circuit board which is constructed of a copper clad phenolic board. The holes to be punched in the board are positioned-at the intersections of a grid pattern which is defined by the spacing between the individual punches of a single row of punches carried in a punching head and the distance which the board is advanced or stepped between each cycle ofthe punching head. The board is advanced in a direr gipii perpendicular to the row of punches.

The, printed circuit board is provided wi nc-ans for positively orienting the board td punches. Referring to Figure 5, this means comprises a pair of notches 13 which are provided in each end of a printedcircuit boardll and adjacent one edge of the board. These notches 13 are necessarily very accurately indexed with respect to the circuit printed on the board 1 1 since the holes to be punched in the board must correspondjvery accurately with the printed circuit. 7 7 Referring how to Figures 1, 2 and 3 of the accompanying drawings, the overall structure of the machine is illustrated. A suitable frame structure is provided which is adapted to support the various moving parts of the machine and includes a substantially rectangular table "elongated opening 17 is provided in the table extends along the front edge of the table for subentire length. A slide carrier 19 for the printed'circuit board 11 is located primarily beneath the surface of the table 15 and is mounted in slides for movement across the machine in a manner which will be described. A portion 'of this carrier extends through "the opening 17 and carries the clamping means which enga es the notches 13 in the printed circuit board to carry the board across the machine. The board is substantially supported by the table 15 and slides along the table being'carried by the carrier 19.

A punching assembly 21 is mounted on the table 15 bridging the area which comprises the path over which the circuit board moves. This assembly includes astrip- {per 23 whichclamps the board 11 against the table 15 during the punching operation and a punching head 25 whieh carries a single row of floating punches. This row of punches is aligned in a direction perpendicular to the path of movement of the board 11. Also mounted on the table 15 and bridging the path of the circuit board 11 is a bank 27 of solenoids. These solenoids are suitably linked to the punching head in a manner which .Will be. described subsequently.

. A pair ofhold-down racks 29 "and 31 are mounted on 'the'table 15 on either sideof the punching assembly. Each of these racks comprises a frame with rollers which are positioned at just sufficient height above the surface of table-15m permit a circuit board to pass beneath it andhen'ce maintain the board flat against the table surface throughout the punching operation. One of these racks29. is hinged so that it may be raised out of the way for'the purpose of placing in or removing a circuit board fromthecarrier 19.

A relatively large rectangular opening 37 is provided the table 15J'toward the rearof the table andperrnits -access, to. a-pairof rotating drums 39 and 41 which are positioned at either end of this opening 37. These drums are provided wfor carrying a pattern ormaster 43 which eontrols the. operation of the punches. The master is made a strip of impregnated glass cloth having holes 45 arranged in a pattern which is identical to the .arrangement of holes to be punched in the circuit board .11.. The holes 45 are positioned at intersections of a grid 'Which'comprise columns extending longitudinally of the strip and transverse rows extending perpendicular to the colum'iis andfspaced apart a distance equal 'to the "amount the master is stepped for each punching cycle. Forconvenience, the' scale of this master may differ from the scale of the circuit board. A reader bar 47 is 'jmounted withintheopening 37 "between the two drums '39ja'nd 4 1. transparent cover 48 is provided for the fopening37 to protect'the exposed mechanism yet permits visual observation. I iThe readerbar'47comprises a single row'of openings are aligned in a direction perpendicular to the direction offinotion 'of the master over the reader bar. j hq eQl fining's correspond to the punches in the punching earl. "Each of the opeiiings'in the reader bar is con fiected ts'a'eharnber associated with an individual pressure operated microswit ch which is normally maintained 'in'the openpositionl The climbers maintained under vacuum. When the "machine is operating, circuit 4 t board 11 passes under the punching head 25 in synchronism with the passing of the master 43 over the reader bar 47. When a hole 45 in the master is positioned over an opening in the reader bar 47, the vacuum in the associated chamber is broken and the associated switch is caused to close. The switch causes one of the electromagnetic devices to be energized causing the punch corresponding to the particular hole 45 in the master to punch a hole in the circuit board 11.

Referring now toFigure 4 a sectional view of the punching assembly 21 is illustrated. The punching head 25 carries a plurality of punches .53 aligned in a single row which extends perpendicular to the plane of the drawing in Figure 4. These punches are substantially cylindrical in shape having a portion of smaller cross section at the punching tip and having an enlarged head at the upper end. The punches are carried in a lower flange 55 which extends laterally from the punching head 25. This flange is provided with vertical cylindrical apertures within which the punches move freely and are supported within the apertures by the enlarged heads. An interference bar 57 is provided for each of the punches 53. These bars are made up of rigid metallic strips which extend laterally through the punching head in a direction perpendicular to the row of punches. The bars move freely in slots provided in thepunchinghead and, when fully inserted into these slots, the ends of the interference bars extend over the upper end surfaces of the enlarged heads of the punches 53. In this position of an interference bar 57, a punch 53 is restricted from vertical movement; hence when the punching head 25 descends toward the circuit board the punch will be forced through the circuit board. If, however, an interference bar 57 is partially withdrawn from the punching head 25, the punch corresponding to that interference bar will be permitted to move upwardly a limited distance. This distance is sufficient so that, as-the punching head descends, when a punch engages the upper surface of a circuit board 11 it will merely ride upward relative to the punching head during the continued downward movement of the punching head and no hole will be punched in the circuit board. A stop bar 61 is provided to limit the amount by which the interference bar may be withdrawn from the punching head. The mechanism for operating these interference bars will be described subsequently.

I The stripper 23 is provided with a laterally extending flange 63 which extends beneath the punching head 25.

This flange is provided to hold the circuit board 11 tightly to the table 15 in the immediate area. the punches 53 and is provided with a row of apertures 65 permitting the punches 53 to pass downwardly through the flange. The table 15 and the area immediately beneath the punching head comprises a die plate 67 having a row of die apertures 69 corresponding to the punches 53. An enlargedchamber 71 beneath the die apertures may be associated with a suction system whereby the punched out portions of the circuit boards may be drawn into a refuse container.

Referring now especially to Figures 2 and 3, the operating mechanism for the punching assembly 21 compriSescrank shaft 77 which is supported in bearings adjacent either end'of the shaft 'ahd'is horizontally disposed beneath the punching head 25. The crank shaft 77 is driven through a gear 79 which is rigidly fixed to the shaft. The gear 79 is in turn coupled to a suitable power source and clutch arrangement 80. These portions '80 of the machine are not described in detail since such description is not deemed essential to the disclosure of the present invention. Each end of the shaft is provided with an eccentric portion 81 which'acts as a crank. These cranks are phased to operate in unison. Each of these eccentric portions 81 is enclosed by an eccentric housing 83which is pivotally attached to the lower'end of 'a rod 85. Eachof the rods 85 is rigidly fixed at its upper "end to end or" the punching head 25. The rods 85 are slidably supported the machine frame to permit only a reciprocating movement in a vertical direction. The shaft 77 then drives the punching head 25 through the eccentrics 81.

,A pair of rods 91 are rigidly attached to either end of the stripper 23 and extend downwardly in a vertical direction just inside of the rods 85. These rods are also slidably supported in the machine frame to permit only a vertical reciprocating motion. Each of the rods 91 is provided with an annular flange or collar 93 at a point intermediate its ends. Each of these flanges 93 provides an upper bearing surface for a coil spring 95 whose lower bearing surface is a portion of the machine frame 97. This coil spring 95 biases the rods 91, and therefore the stripper 23, toward its upper limit, that is, to a position where the stripper will not clamp a circuit board 11 against the table 15. A coupling member 99 is attached adjacent the lower end of each of the rods 91 to provide a fulcrum by 'means of which a reciprocating motion is imparted to the rods 91. i A stripper shaft 101 is rotatably mounted in the machine frame and extends parallel to the crank shaft 77. A pressure lever 105 is rigidly fixed to each end of the stripper shaft 101 and each of these pressure levers 105 engages a coupling member 99 which is attached to one of the rods 91. A cam lever 107 is rigidly fixed to the stripper shaft 101 at a point intermediate the ends of the stripper shaft. This lever 107 is attached at one end to the shaft 101 and its other end extends downwardly to a point adjacent the crank shaft 77. A cam 109 is fixed to the crank shaft 77 and engages a cam follower 111 which is carried by the cam lever 107. The combination of the cam lever 107, stripper shaft 101, and pressure lever 105, form a bell crank arrangement through which the rods 91 are driven downwardly by means of the cam 109. 5 Hence the stripper 23 is caused to clamp acircuitboard 11 against the table 15 by the positive action of the cam 109 and its associated mechanism. At the end of the punching cycle, after the punches have been withdrawn from the board, the cam 109 permits the stripper to be raised from clamping engagement and this upward force is provided by the coil springs 95.

Referring now to Figures 6 and 7 the carrier 19 comprises a frame having mounted thereon a pair of horizontally extending racks 117 and 119 which are disposed in parallel relation, with each other one above the other and, at its upper surface, a clamping mechanism for rigidly clamping a circuit board 11 to the carrier 19. The upper rack 117 is rigidly fixed to the carrier frame and is provided for driving the master drum 39 through a coupling mechanism which will be described subsequently. The lowerrack 119 is mounted to be movable in a vertical direction relative to the carrier frame. This motion is provided so that the rack 119, and hence the carrier 19 may be selectively disengaged from the carrier driving mechanism which will be described.

The rack 119 is provided with a pair of apertures 121 having opposing upper and lower edge surfaces which are accurately spaced relative to eachother. Two shafts 123, eachhaving a cam portion 125 intermediate its ends, are rotatably mounted at spaced positions on the carrier frame and extend laterally from the frame in a direction perpendicular to the rack 119. The rack apertures 121 are spaced to correspond with the spacing of the shafts 123 and willv receive the cam portions 125 of these shafts. The cam portions 125 are designed to provide a crank action with respect to the axis of rotation of the shafts 123. As the cams 125 are rotated, the distance between parallel tangents to the cam surfaces remains constant. Therefore when the shafts 123 are oscillated through a given angle, the rack 119 will be caused to reciprocate in a venticaldirectionq i I A crank 127 is fixed to the free endof each of the shafts 123.- These cranks are linked together and operated by appropriate linkage 129, 130 and 131. The two cranks 127 are connected by the link 130 and rotate together. Link 129 is connected at one end to the link 130 and at its other end to a crank 133. The crank 133 is rigidly attached to and manually operated by a lever 135. The link 131 is connected at one end to the link 130 and at'its other end is supported by a crank 137 which is pivotally attached to the carrier frame. This crank 137 extends in a substantially vertical direction. When the carrier 19 is engaged with its driving mechanism, the crank 137 is swung to a position toward the leading end (right hand end in Figures 6 and 7) of the carrier 19. In the event that the means for normally stopping the operation of the machine should fail, when the carrier reaches the limit of its travel, the crank 137 moves into engagement with-a member attached to the machine frame causing the crank 13-7 and associated, linkage to move in the opposite direction thereby disengaging the rack 119 fromgthe carrierdriving mechanism and preventing damage to the machine.

The mechanism for clamping a circuit board 11 to the carrier 19 is mounted on the top surface of the carrier. A pair of jaws 151 and 153 are provided adjacent either end of the carrier 19. Fingers 155 and 157 are provided respectively on the jaws 151 and 153 and extend toward each other to engage the notches 13 provided at either end of the printed board 11. Each of the jaws 151 and 153 is attached to the end of an arm 159 and 161. These arms are aligned in a longitudinal direction and the ends of the arms opposite from the jaws are adjacent each other in a near abutting relationship. A shaft 163 extends from one end of the carrier 19 to the point where the butting ends of the arms 159 and 161 are adjacent each other. This end of the shaft is provided with two threaded portions 165 and 167 which are adjacent each other and which have reverse threads provided thereon. A pair of blocks 169 and 171 are mounted on the threaded portions 165 and 167 of the shaft 163. The blocks 169 and 171 are attached respectively to the adjacent ends of the arms 159 and 161. When the shaft 163 is rotated the arms 159 and 161 are moved either toward each other or away from each other and a corresponding movement is imparted to the jaws 151 and 153. A knob 173 is coupled to the shaft 163 by means of bevel gears 165 and 167 and provides the means for manually opening and closing the jaws 151 and 153 for the purpose of locking or releasing a circuit board 11 from the carrier 19.

Referring now especially to Figures 2 and 3, the driving mechanism for the carrier 19 includes a gear which is rigidly mounted on the crank shaft 77 and which meshes with a gear 187. The gear 187 carries a Geneva drive 189 which engages a Geneva plate 191 to provide an intermittent motion for the carrier 19. The Geneva plate 191 carries a pinion 193 which meshes with one of a pair of gears 195 and 197 which rotate together by means of a shear connection. The shear connection will, of course, fracture should the machine be overloaded. The gear 197 engages the rack 119 of the carrier 19.

The driving mechanism for the drum 39 comprisesa pair of aligned shafts 205 and 207 which are coupled together by a phase shifting mechanism which will be described. The shaft 207 is directly coupled to the drum 39. The shaft 205 has a gear 209 rigidly fixed to one end which meshes with the rack 117 of the carrier '19.

Referring now to Figures 8 and 9, the phase shifting mechanism comprises a U-shaped housing 211 whichis pivotally mounted about the axis of rotation of the shafts 205 and 207. The adjacent ends of these shifts extend into the housing 211 and carry rigidly fixed gears 213 and 215 respectively on the shafts 205 and 207. The member 217 having two integral gear portions is rotatably mounted within the housing 211 about an axis parallel withtheaxes of the shafts 205 and 207. The gear portions of the member 217 mesh with the two gears 213 and: 215 to provide a constant coupling between the shafts 205 and 207 and hence between the carrier 19 andthe drum'39. 1

The mechanism just described is anoseillating plane 7 tary. The mechanism is oscillated about the axes of the shafts 205 and 297 by means of a link arm 219 which is attached at one end to the housing 211 at a point removed from the axis of the shaft 205 and is attached at its other end to one end of a rocker arm 221 which is rotatably mounted on a fixed shaft 223. A dififerential cam 225 is rigidly attached to the crank shaft 77 and is engaged by a cam follower which is attached to the other end of the rocker arm 221. By means of the differential cam 225, the oscillating planetary is caused to oscillate in timed relation with the intermittent motion of the carrier 19. When the carrier 19 is advanced and the shaft 205 is consequently rotated through a fixed angle, the housing 211 is simultaneously rotated through a fixed angle about its mounting axis in a manner such that no rotation is imparted to the gear 215 and consequently to the shaft 2&7 and the drum 39. When the carrier motion is stopped and the shaft 205 has ceased to rotate, the housing 211 is rotated in a reverse direction to return to its original position thereby imparting rotation to the shaft 207. The net effect of this mechanism then is to delay the driving of the drum 39 by the carrier 19 without effecting the angle through which the drum is rotated.

Referring now to Figures 10 and 11 the drums 39 and 41 are rotatably mounted parallel each other and are provided respectively with paper anchoring slots 4! and 42. The drum 39 is directly connected to the shaft 297 through a flange coupling 231 and is the driving drum for the master 43. The drum 41 is the storage drum for the master 43. In order to provide tension on the master 43 when it is attached to the drums, a Negator motor 233 is coupled to the drum 41. This Negator motor comprises a coiled spring 235 which is coiled about an axis parallel to the axis of rotation of the drum 41 and one end of which is secured to an axial projection of the drum 41. As the master is drawn from the storage drum 41 by the driving drum 39 the spring will wrap around the axial projection of the drum 41 uncoiling from its original position. The Negator motor is designed'so that a back tension applied by the spring as it uncoils is substantially constant within the operating limits of the motor. This Negator motor then provides a constant tension on the master as it is being drawn from the storage drum 41 and also provides for the rewinding of the master on the storage drum after a machine cycle has been completed and it is desired to return the carrier and master to their starting positions. g The reader bar 47 is disposed between the drums 39 and 41 and comprises an elongated member having a smooth upper surface 241 which has a rounded sectional contour. The surface 241 is provided with a single row of apertures 243 which extend into the reader bar 47 and provide individual chambers within the reader bar. Means are provided for connecting an air conduit 244 to each of the individual chambers provided in the reader bar 47. A plurality of banks 245 of pressure operated switches 247 are attached to the reader bar 47 and extend downwardly from the reader bar. Each bank 245 comprises an elongated vertically extending tubular member 249 which is rectangular in cross section. A row of spaced openings 251 are provided along one surface of the tubular member 249. One of these openings 251 is illustrated in Figure 12. These openings 251 are each closed by a diaphragm 253 having a rigid disc member 255 secured to the diaphragm and disposed centrally of the aperture 251. A pin 257 is rigidly fixed to the disc member 253 and extends perpendicularly from the disc member across the tubular member 249 and through a small opening in the side of the tubular member opposite from the diaphragm opening 251. The switches 247 are mounted on the tubular member 251 and are actuated by the pins 257. A helical compression spring 259 is disposedwithin the tubular member 249 around each of the pins 257 and biases the disc member 255 to hold the pin out of engagement with the switch 247.

Each of the diaphragm openings 251 in the tubular member 249 is covered by a housing 261 to provide a closed chamber 263 at the outer surface of each of the diaphragms 253. Each of these chambers is connected, by means of previously mentioned air conduits 244 to an individual chamber associated with one of the apertures 243 in the reader bar 47. A bleeder passage 265 is provided between each of the chambers 263 and the interior of the tubular member 249. When the machine is operating, a vacuum is applied to the chamber of the tubular member 249 and a negative pressure is maintained within a chamber 263 when its corresponding aperture 243 in the reader bar 247 is sealed off by the master 43. When one of the holes 45 in the master 43 is positioned over an aperture 243 in the reader bar 47, atmospheric pressure is admitted to the corresponding chamber 263 and the differential pressure acting on the diaphragm 253 between the chamber 263 and the chamber within the tubular member 249 is suflicient to overcome the force of the spring 259 and to move the pin 257 to actuate the switch 247. The blee'der passage 265 is suificiently small so that the vacuum within the tubular member is not significantly reduced. When the master is again moved across the reader bar 47 so that the chamber 263 is again sealed off -rom the atmosphere, the vacuum is restored to the chamber 263 by means of the bleed 265 to again equalize the pressures on both sides of the diaphragm 253 permitting the spring 259 to return the pin 257 to its original position.

Referring again to Figures 2 and 3 of the mechanism for operating the interference bars 57 will now be described. This mechanism includes a bank of solenoids 27 which is mounted above the path of the circuitboard 11. A solenoid is provided for each of the interference bars and these solenoids are disposed so that the movable member moves in a direction substantially parallel to the movement of the interference bars 57. A pair of brackets 273 support a plurality of shafts 275. Each of these shafts supports a plurality of rocker arms 277 mounted for rotation with respect to the shaft. The rocker arms 277 extend in a substantially vertical direction and each of the rocker arms is connected at its lower end to one of the interference bars 57 by means of a suitable link 279. Each of the rocker arms 277 is connected at its upper end to the movable member ofone of the solenoids 271 by means of a suitable link 281. A compression spring 283 is associated with each of the links 281 and acts to bias the links 281, and consequently the plungers of the solenoids 27'1, toward the right (referring to Figure 2). Through the rocker arms 277, the interference bars 57 are biased toward the left or tothe position where the punches will not be actuated by the punching head. Each of the solenoids 271 is electrically connected to one of the switches 247. When a switch 247 is closed, its corresponding solenoid 271 is actuated to place an interference bar 57 in position over its corresponding punch 55 whereby a hole is punched in a circuit board.

The machine which has been described above is designed for a circuit board 11 having a standard length and having indexing notches 13 of standard size placed av standard distance from the edge of the board. The circuit board may be of any width within the limit which is determined by the number of punches provided in the punching head.

The glass cloth master 43 is punched with holes which are arranged in the pattern which is to be punched in the circuit board. The master is attached to the drums 39 and 41 in the paper anchoring slots 40 and 42. The machine is set up so that when the carrier 19 is set in its starting position (the position illustrated in Figure 2), the angular position of the anchoring slot 40 in relation to the drum 39 is fixed so that the leading edge of the master 43 extends a fixed distance past the reader bar 47 when it is attached to the drums. This is necessary so that the hole pattern provided on the master will always the drum 39 is advanced by means of the oscillating planetary drawing the master 43 over the reader bar 47 a predetermined distance. Through this arrangement,

the advancement of the hole pattern onthe master across the reader bar is timed to be approximately one half cycle ahead ofthe advancement of the circuit board. Hence when the carrier is stopped during the punching of a transverse row A of apertures in a circuit board, the drum 39 advances the master so that a transverse row B of apertures 45 in the master is positioned over the reader bar. As soon as this occurs the solenoids corresponding to these apertures will be energized throughthe described vacuum switching mechanism and will attempt to set up the corresponding interference bars 57 in the punching head 25. These interference bars 57 may not move in over the punches however until the punching head 25 moves upwardly permitting the punches to drop to their normal rest positions on the flange 55. As the punching head moves upwardly the master 43 is maintained in this position over the reader bar 47 while the circuit board is advanced beneath the punching head. As the punching head descends to punch the row B of apertures in the circuit board 11 the drum 39 again advances the master 43 to position a tranverse row C of apertures in the master over the reader bar. The advantage of this alternating movement of the master -43 and the circuit board 11 is that considerably more punches per unit of time can ,be made without increasing the speed of the operating mechanism. If these two members were advanced simultaneously a delay time would be required to permit interference bars to be set up in the punching head before the punch head could be moved downwardly to punch the circuit board. I 1

It will be noted that all of the moving parts ofthe machine are driven through the crank shaft 77. The cam 109 is attached to the crank shaft 77 in a fixed angular relation with the eccentric portions '81. The timing is fixed so that the cam 109 will cause the stripper to clamp a circuit board 11 tightly against a die plate '67 immediately before the punches 53 are forced through the circuit board by the eccentrics 81. By the same token the stripper 23 is maintained in this position until the punches 53 have been completely withdrawn from the circuit board 11 to prevent any upward movement of the circuit board. As soon as the punches have been withdrawn from the board the stripper pressure is released permitting the board to be advanced for the next punching cycle. As previously described, the advancing mechanism for the carrier is directly driven from the crank shaft 77 as is the cam 225 which controls the timing for the coupling mechanism between the carrier 19 and the drum 39. As a result of this arrangement it is a simple matter to adjust and maintain the timing between various components of the machine.

What is claimed is:

1. In a machine for producing a punched panel under control of a master, means for sensing said master, means comprising a plurality of punches for punching said panel, means for intermittently stepping said panel past said punches, means for intermittently stepping said master past said sensing means, means directly coupling said panel stepping means and said master stepping means in positive geared relation, said coupling means providing for varying in a predetermined manner the timed relationship of the stepping of said master with respect to the stepping of said panel, means for selectively engaging and disengaging said coupled stepping means from'a drive source without disturbing said timed relationship, means under control of said sensing means for selecting individual ones of said punches, and means for actuating said selected punches to punch said panel to correspond with the pattern of said master. I

2. In a machine for punching a panel under control of a master having a plurality of columns of perforations, a plurality of punches, each punch thereof being correlated with a column of said perforated master and each punch being adapted to punch in any one of a plurality of positions in a master column, a plurality'of pressure responsive control elements adapted to cooperate with said master, a carrier for said panel, means comprising intermittent drive gearing for driving said carrier intermittently past said plurality of punches, means for selectively disengaging said carrier from said intermittent'drive gearing, means for carrying said perforated master past said'pressure responsive control elements, means directly coupling said master carrying means and said carrier in definite phase relationship, a plurality of switches actuated by said control elements, a plurality of electromagnetic devices energized by said switches, and means actuated by said electromagnetic devices for selecting said punches so that said panel is punched to correspondwith said master.

3. In a machine for punching a panel in accordance with a master, punching means comprising a plurality of spaced punches, a punch support member, means for driving said punches by said member, a slide for supporting said panel, said slide comprising a pair of racks, an intermittent drive mechanism associated with one of said racks for stepping said slide beneath said punch driving means, means for selectively disengaging said one rack from said intermittent drive mechanism, a sensing means, means for carrying said master over said sensing means, said carrying means comprising a pair of drums, means directly coupling one of said drums and said other rack whereby said master and said slide are always positively indexed with respect to each other,'and means associated with said other drum for maintaining a constant tension on said master between said drums.

4. In a machine for punching a panel under control of a perforated master, said master having holes aligned in columns and spaced at predetermined intervals in said columns, a line of punches each being correlated with a column of said perforated master and each being adapted to punch in any one of a plurality of positions ina master column, a carrier for supporting said panel for carrying said panel beneath said line of punches, means comprising intermittent drive gearing for feeding said carrier intermittently beneath said line of punches, a rack associated with said carrier adapted to mesh with said intermittent drive gearing, means for disengaging said rack from said intermittent drive gearing, a plurality of solenoids each for controlling one of said punches, a plurality of switches each for actuating one of said solenoids, a plurality of switch control elements for actuating said switches, said switch control elements being responsive to differential pressure, means whereby each switch control element is controlled by one column of said perforated master, means for carrying said master past said last mentioned means whereby each switch control element is controlled, and means directly coupling said carrier and said master carrying means whereby said master and said panel are always in perfect registry with each other.

5. In a machine for punching a panel under control of a flexible perforated master, said master having holes aligned in columns and spaced at predetermined intervals in said columns, a line of punches each being correlated with a column of said perforated master and each being adapted to punch in any one of a plurality of positions in a master column, a carrier for supporting said panel and for carrying said panel beneath said line of punches, means comprising intermittent drive gearing for feeding said carrier intermittently beneath said line of punches, a rack associated with said carrier adapted to mesh with said intermittent drive gearing, means for selectively disengaging sa'idrack from said intermittent drive gearing whereby said carrier may be positioned manually, sensing means adapted to cooperate with said master, means responsive to said sensing means for setting up individual ones of said punches, .means comprising a driving drum and a storage drum for feeding said master past said sensing means, means directly coupling said carrier and said driving drum whereby said master and said panel are always in perfect registry with each other, and a spring motor associated with said storage drum, said motor providing constant tension on said master as it is drawn from said storage drum to said driving drum.

6. In a machine for punching a panel under the control of a perforated master, said master having holes aligned in columns and spaced at predetermined intervals in said columns, means for advancing said panel in intermittent steps, means directly coupled to and in timed relation with said panel advancing means for advancing said master, a punching head mounted over the path of said panel, a plurality of floating punches carried in said punching head, each of said punches being correlated with'a column of said perforated master and each being adapted to punch in any one of a plurality of positions in a master column, means under control of said perforated master for selecting individual ones of said punches, a die plate mounted beneath said punching head, a stripper for clamping said panel against said die plate, a crank shaft, said panel advancing means being directly driven from said shaft, means for selectively engaging .and disengaging said panel advancing means from said shaft without disturbing said timed relationship between said panel and said master, cam means associated with said shaft for drawing said stripper against said die plate, and crank means associated with'said shaft for driving said punching head toward said 'die plate, said stripper being maintained in clamping relationship with said die plate throughout the cycle of said punching head.

7. In a machine for punching a printed circuit board in accordance with a perforated master, sensing means including a reader bar having a row of spaced passages terminating at its upper surface, punching means including a plurality of spaced punches aligned in a row over a punching die, a single mechanically driven member for driving all of said punches, an interference bar for each of said punches adapted to be positioned between the same and said member whereby the latter may drive said punches through the medium of said interference bars, a control solenoid for each interference bar adapted to position the bar between its punch and said member only during the time said solenoid is energized, a pressure operated switch for each solenoid, a housing associated with each switch comprising two chambers separated by a diaphragm, each of said housings being provided with a bleeder passage between said chambers, actuating means for said switches mounted on said dia phragms, one of said chambers in each of said housings adapted to be placed under a vacuum, means connecting one of said reader bar passages to said other chamber of each of said housings, means for biasing each of said diaphrams toward said chamber connected to said reader bar, means for carrying said perforated master over said reader bar in intermittent steps, means for carrying said printed circuit board beneath said punch driving member in intermittent steps, means directly coupling together said carrying means, said coupling means providing for alternation of steps of said printed circuit board and said perforated master, means for selectively engaging and disengaging said coupled carrying means from a drive source, and means for locking said printed circuit board against said punching die during each punching operation.

References Cited in the file of this patent UNITED STATES PATENTS 726,676 Gregor Apr. 28, 1903 805,192 Gadd Nov. 21, 1905 1,257,836 Ferris Feb. 26, 1918 1,294,845 Stoddard Feb. '18, 1919 1,323,614 Stoddard Dec. 2, 1919 1,400,242 Stoddard Dec. 13, 1921 1,432,424 Stoddard Oct. 17, 1922 1,472,027 Salyer Oct. 23, 1923 1,588,831 Yokoyama June 15, 1926 1,902,064 Ford Mar. 21, 1933 2,261,710 Andrews Nov. 4, 1941 2,294,371 Andrews Sept. 1, 1942 2,340,800 Doty Feb. 1, 1944 2,375,293 Doty May 8, 1945 2,566,704 Leibing Sept. 14, 1951 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. 2,911,045 November 3, 1959 Theodore M. Wright It is hereby certified that error of the above numbered patent requiring Patent should read as corrected below.

appears in the printed specification correction and that the said Letters Column 12', list of References Cited, under UNITED STATES PATENTS, after line 47 insert the following:

2,294,370 AndreWs---Sept., 1', 1942 Signed and vsea.il -ed thig 10th day of May 1960 (SEAL) Attestz- KARL .AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents 

